Fig. 1: A multiplexed quantum network.
a The schematic of a multiplexed trapped-ion quantum network. There are two kinds of qubits in each network node. The communication qubits (green, red, blue, orange) are used for distributing heralded entanglement between different nodes, and the memory qubits (grey) are responsible for storing local quantum information or carrying out local computing tasks. Entanglement between distant nodes is heralded via interfering the photons on a beamsplitter in the middle point of the two nodes. The entanglement distribution task can be accelerated via different multiplexing schemes. In this work, multiplexing-enhanced ion-photon entanglement is realized as highlighted in the dashed box (other parts are not realized). b The protocol of a time-bin multiplexing scheme. Totally N temporal modes are excited in one run of entangling attempts, and the corresponding heralding signal returns to the node after a round-trip travel time of \(\frac{2L}{c}\) following the excitation. c Enhancement factor in time-bin multiplexing. The enhancement factor M starts saturating when the duty cycle of the entangling attempts reaches 50%. Here \({N}_{0}=(\frac{2L}{c}+{T}_{{{{\rm{ovh}}}}})/\Delta t\) is the characteristic number when the duty cycle reaches 50% (Tovh is the averaged time overhead in each round which mainly include the initialization and cooling period in the experiment).
